LASER-INDUCED FLUORESCENCE IN MgO: DIRECT OBSERVATION OF THE LOWEST $^{3}\Pi$ STATE AND THE ANALYSIS OF PERTURBATIONS IN THE GROUND STATE
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Date
1975
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Publisher
Ohio State University
Abstract
Fluorescence spectra of gaseous MgO induced by $Ar^{+}$ laser-innes have been studied, MgO was generated by the reaction between magnesium vapor and $N_{2}$O. The laser coincidences in the $B^{1}\Sigma^{+} - $X$^{1}\Sigma^{+}$ band system are the following. a) 4765 {\AA} line: R(26) of the 5-4 band, R(49) of the 4-3 band, and R(70) of the 3-2 band, all with $^{24}MgO$.b) 4965 {\AA} line: R(36) of the 2-2 band of $^{26}MgO$.c) 5145 {\AA} line: P(10) of the 4-5 band of $^{24}MgO$, R(25)of the 3-4 band of $^{26}MgO$, R(50) of the 2-3 band of $^{25}MgO$, and R(70) of the 1-2 band of $^{24}MgO$. Each B-X excitation, in general, gives rise to band progressions extending to hither vibrational levels of both the $X^{1}\Sigma^{+}$ and the $A^{1}\Pi$ state that have not been rotationally analysed. Perturbations in the $X^{1}\Sigma^{+}$ and the $A^{1}\Pi$ state have been discovered. The former is believed to be due to the lowest $^{3}\Pi$ state. Perturbation-induced $B^{1}\Sigma^+ - ^{3}\Pi$ transitions (10 lines) which accompany the strongly perturbed lines have been confirmed, thus allowing the first observation of the lowest $^{3}\Pi$ state. Calculations are in progress to determine the spectroscopic constants, the spin-orbit coupling constants and the perturbation matrix clement of the $^{3}\Pi$ state, but the preliminary treatment places its potential bottom $\sim 900 cm^{-1}$ below the $A^{1}\Pi$ state- This result will facilitate the future analysis of the B-X band system with $v > 2$. Population of the A-state molecules $(T_{e} = 3563 cm^{-1})$ in the flame has been detected through fluorescences induced by a tunable dye laser (Rhodamine 6G) and It confirmed the symmetry of the A-state as $^{1}\Pi$
Description
This work was supported, in part, by AFOSR.""
Author Institution: University of California
Author Institution: University of California